On the results reported below the plant extracts used according to the present invention are identified by their respective original coded name, with the following correspondence:                L-18: Artocarpus heterophyllus seed extract,        L-19: Cyathea cumingii leaf extract (polar solvent extraction),        L-20: Secale cereale seed extract (polar solvents extraction, in particular water, followed by an enzymatic hydrolysis),        L-21: Secretion of Thalassiosira pseudonana (obtained from a culture in sea water),        L-22: Soy seed pericarp extract (aqueous suspension followed by an enzymatic hydrolysis),        L-23: Buddleja axillaris leaf extract (extraction/concentration, then lyophilisation/sterilisation).        
This report presents data on the effect of various L-18-23 on melanosome transfer in normal human epidermal melanocytes to fully matched epidermal keratinocytes.
The optimal doses have been standardized for each plant extract active separately on epidermal melanocytes and keratinocytes. The effect of all L-18-23 on a) melanin synthesis and b) tyrosinase activity using melanocytes cultured alone and cultured together with matched keratinocytes (i.e., EM-KC co-cultures) has been assessed. The effects of the plant extracts actives on melanosome transfer in EM: KC co-culture using gp00 immunolabelling has been evaluated.
Both positive melanocyte modulator (IBMX) and a melanosome transfer inhibitor (Niacinamide) were used as control for this study.
In general, L-18, 19, 20, 21, 23 downregulated melanin synthesis, dopa-oxidase activity of tyrosinase, melanosome transfer, and Myo-X expression. In fact, L-18 and L-23 were known as depigmentating agents but their action on these parameters was not shown so far. By contrast, L-22 was found to upregulate said parameters.